U.S. patent number 5,187,225 [Application Number 07/427,525] was granted by the patent office on 1993-02-16 for sealant compound with carbon fiber mixed therein.
This patent grant is currently assigned to Kitagawa Industries Co., Ltd.. Invention is credited to Hiroji Kitagawa.
United States Patent |
5,187,225 |
Kitagawa |
February 16, 1993 |
Sealant compound with carbon fiber mixed therein
Abstract
The sealant compound of this invention comprises polyurethane
resin or its precursor mixed with vapor grown carbon fiber. In the
compound, whisker-shaped carbon fibers with high tensile strength
intertwine and form lattices. In addition, carbon fibers are
anchored in the polyurethane resin. Consequently, the compound of
this invention has more tensile strength than the conventional
compound containing black carbon. Thus the seal consisting of the
compound of this invention has high adhesion and sealing
effects.
Inventors: |
Kitagawa; Hiroji (Nagoya,
JP) |
Assignee: |
Kitagawa Industries Co., Ltd.
(Aichi, JP)
|
Family
ID: |
17592818 |
Appl.
No.: |
07/427,525 |
Filed: |
October 27, 1989 |
Foreign Application Priority Data
|
|
|
|
|
Nov 2, 1988 [JP] |
|
|
63-278114 |
|
Current U.S.
Class: |
524/847; 524/871;
524/872; 524/873; 524/874; 524/875 |
Current CPC
Class: |
C08K
7/06 (20130101); H05K 9/0015 (20130101); H05K
9/009 (20130101); C08K 7/06 (20130101); C08L
75/04 (20130101) |
Current International
Class: |
C08K
7/06 (20060101); C08K 7/00 (20060101); H05K
9/00 (20060101); C08K 003/4 (); C08L 075/04 () |
Field of
Search: |
;524/871,872,873,874,875,847 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
0267603 |
|
Nov 1986 |
|
EP |
|
2608549 |
|
Feb 1986 |
|
FR |
|
60-159031 |
|
Aug 1985 |
|
JP |
|
63-286437 |
|
Nov 1988 |
|
JP |
|
1297585 |
|
Mar 1971 |
|
GB |
|
1486033 |
|
Feb 1975 |
|
GB |
|
Primary Examiner: Marquis; Melvyn I.
Assistant Examiner: Dean; Karen A.
Attorney, Agent or Firm: Oliff & Berridge
Claims
What is claimed is:
1. A sealant composition comprising:
polyurethane resin; and
between 5% and 30% by weight of vapor grown carbon fibers
manufactured by a vapor phase system in which ultra fine particles
of high melting metallic compound are suspended on a floating bed
in a three dimensional reaction zone in which hydrocarbon is
thermally decomposed, based on 100% by weight of said polyurethane
resin;
where said carbon fibers are mixed into the polyurethane resin so
that said carbon fibers enhance the physical strength of the
polyurethane resin; and
wherein said sealant composition has a rubbery elasticity.
2. The sealant composition of claim 1, wherein the carbon fibers
are whisker shaped.
3. The sealant composition of claim 1, wherein the carbon fibers
are mixed into a precursor of the polyurethane resin prior to
curing.
4. The sealant composition of claim 3, wherein the precursor is a
single-liquid form of precursor.
5. The sealant composition of claim 3, wherein the precursor is a
double-liquid form of precursor.
6. The sealant composition of claim 1, further comprising additives
chosen from the group consisting of fillers, plasticizers,
deteriorization-preventative agents, and resins for providing
adhesion, where at least one such additive is mixed into the
polyurethane resin to modify the properties thereof.
7. The sealant composition of claim 1, wherein said carbon fibers
are less than 1 mm in length.
8. The sealant composition of claim 1, wherein the content of vapor
grown carbon fiber manufactured by a vapor phase system in which
ultra fine particles of high melting metallic compound are
suspended on a floating bed in a three dimensional reaction zone in
which hydrocarbon is thermally decomposed, in said sealant
composition is 20% to 30% by weight based upon 100% by weight of
said polyurethane resin.
9. The sealant composition of claim 1, wherein said carbon fibers
are vapor grown carbon fibers.
10. A sealant composition consisting essentially of:
polyurethane resin; and
between 5% and 30% by weight of vapor grown carbon fibers
manufactured by a vapor phase system in which ultra fine particles
of high melting metallic compound are suspended on a floating bed
in a three dimensional reaction zone in which hydrocarbon is
thermally decomposed, based on 100% by weight of said polyurethane
resin;
where the carbon fibers are mixed into the polyurethane resin so
that the carbon fibers enhance the physical strength of the
polyurethane resin; and
wherein said sealant composition has a rubbery elasticity.
11. A sealant composition of claim 1, wherein said metallic
compound is selected from the group consisting of vanadium,
niobium, tantalum, chromium, molybdenum, manganese, cobalt, iron,
nickel and oxides, chlorides and nitrides thereof.
12. A sealant composition of claim 1, wherein said fine particles
of metallic compound crown said vapor grown carbon fibers.
Description
BACKGROUND OF THE INVENTION
This invention relates to a sealant compound for sealing and
filling a gap.
In related arts, various kinds of resins are used for a sealant.
The sealant fits the gap in a housing using its rubber-like
elasticity to secure the contents of the housing and prevent the
contents from being interfered with from the outside. For example,
an O ring made of synthetic resin, or a synthetic resin packing
adaptable to the configuration of the gap is used. Another known
sealant is an adhesive compound that can also be used as an
adhesive. In addition, a sealant for sealing joints in the housing
of an automobile transmission, a sealant for shielding an
automobile windowpane, and a sealant for sealing joints in an
architectural panel are known.
To enhance the strength of the seals having rubber-like elasticity
so that they can be used in severe conditions, various compositions
of known resin, filler, plasticizer or other materials that govern
the physical strength of the seals are reviewed. The reviewed
compositions only provide a limited strength to the seals,
however.
SUMMARY OF THE INVENTION
An object of this invention is to provide a sealant compound having
enhanced physical strength.
This object is attained by a sealant compound with carbon fiber
mixed therein. The sealant compound comprises polyurethane resin
and carbon fiber. The carbon fiber is mixed with polyurethane resin
or a precursor of the polyurethane resin. The carbon fiber is
manufactured through a vapor-phase system. In the vapor-phase
system, ultrafine particles of a high-melting metal or its compound
are suspended in the zone in which hydrocarbon is thermally
decomposed.
Polyurethane resin is generally produced by reacting polyisocyanate
with polyol, water, polyamine, aminoalcohol, etc. and curing
("Polyurethane Resin, Journal of Plastics Material 2" published by
Japan Daily Industrial Newspaper Co. Ltd.).
The precursor of polyurethane resin is a substance that precedes a
chemical reaction for producing polyurethane resin, such as
polyisocyanate, polyol, water, polyamine, aminoalcohol, or the
like. The precursor can be supplied in a single-liquid form or
double-liquid form. The single-liquid type of the precursor can
change to a rubberlike elastic body by reacting with moisture in
the air. The double-liquid type of the precursor can be changed to
the rubberlike elastic body by mixing a first liquid with a second
liquid.
In addition to the carbon fiber, known compounds can be mixed with
the polyurethane resin.
The carbon fiber is manufactured through a vapor-phase system by
suspending ultrafine powder of high-melting metal or high-melting
metal compound in the thermal decomposition zone of hydrocarbon.
The carbon fiber is whisker-shaped, as disclosed in Japan Published
Examined Patent Application No. 62-242 and Japan Published
Unexamined Patent Application Nos. 60-27700, 62-95351, 60-38472,
and 59-179816. The high-melting metal does not gasify at
950.degree. C. to 1300.degree. C., the temperature range in which
hydrocarbon is thermally decomposed. For the high-melting metal,
available is titanium (Ti), zirconium (Zr) or the like in group IVa
according to the periodic system, vanadium (V), niobium (Nb) or
tantalum (Ta) in group Va, chromium (Cr), molybdenum (Mo) or the
like in group VIa, manganese (Mn) or the like in group VIIa, or
iron (Fe), cobalt (Co), nickel (Ni) or the like in group VIII.
Metals Fe, Co, Ni, V, Nb, Ta, Ti, and Zr are best. The oxide,
nitride, chloride or the like of the metals is used as the
high-melting metal compound.
Japan Published Examined Application No. 62-242 discloses a method
of successively manufacturing carbon fiber having branches by a
vapor-phase system in which ultrafine particles of a high-melting
metal and/or high-melting metal compound are suspended on a
floating bed in a three-dimensional reaction zone. Hydrocarbon is
thermally decomposed in a thermal decomposition zone of hydrocarbon
in which the ultrafine particles of a high-melting metal and/or a
high-melting metal compound are floated.
In Japan Published Unexamined Patent Application No. 60-27700,
carbon fiber is prepared continuously and with high efficiency by
introducing a compound containing a transition metal to a zone to
precipitate carbon fiber, decomposing it thermally, and
precipitating particles of the transition metal on a substrate. The
substrate is set at a carrier gas inlet of a reaction equipped with
nichrome wire and the substrate is introduced into the reactor in a
horizontal direction at .ltoreq.3.0 cm/min linear speed. The
reaction temperature is maintained at 1,000.degree.-1,300.degree.
C. and the substrate at .ltoreq.1,120.degree. C. A mixed gas of a
gas of an organic compound containing a transition metal of the
formula M(C.sub.2 H.sub.5).sub.2 (where M is a transition metal), a
hydrocarbon gas, and a carrier gas is fed to the reactor. The
hydrocarbon is thermally decomposed by catalytic action of the
transition so that carbon fiber is formed on the substrate.
Japan Published Unexamined Application No. 62-95351 discloses a
method of obtaining carbon black of composite structure
continuously and efficiently by adding a metallic compound in a
gaseous state to a furnace and carrying out a thermal decomposition
reaction of an acetylene gas and form fibrous carbon by a gaseous
phase method in the same furnace simultaneously. A reaction furnace
is charged with a metallic compound (e.g. ferric nitrate, cobalt
chloride, etc.) in a gaseous phase, an acetylene gas, a carrier gas
(preferably hydrogen gas) and, if necessary, an unsaturated
hydrocarbon. A thermal decomposition reaction of the acetylene gas
and formation of fibrous carbon by a gaseous phase method are
simultaneously carried out and the fibrous carbon is grown from
carbon particles to give the aimed carbon black of composite
structure. A ratio of the prepared carbon black of composite
structure and the fibrous carbon is preferably 1-200 pts. wt.
fibrous carbon based on 100 pts. wt. carbon black.
Japan Published Unexamined Patent Application No. 60-38472
discloses carbon black having improved electrical conductivity and
processability by carrying fine particles of a metal or a metallic
compound on carbon black and introducing a hydrocarbon gas. Carbon
black is seeded with fine particles of a metal or a metallic
compound and fed to an externally heated tubular furnace. While
keeping the temperature at 900.degree.-1,500.degree. C., a
vaporized hydrocarbon gas and a carrier gas such as hydrogen gas
are introduced to grow fibrous carbon within the voids of carbon
black by a vapor phase method. Fine fibrous carbon having a
diameter of hundreds to thousands of Angstroms starting from the
ultrafine metallic particles supported on the carbon black is grown
within voids between the textures of carbon black while crowning
the fibrous carbon with the ultrafine metallic particle, whereby a
composite structure is formed. It is desirable that the ratio of
the fibrous carbon to carbon black is 50 wt. % or below, the length
of the fibrous carbon is 1 mm or shorter, and the diameter thereof
is 50 .mu. or less.
Japan Published Unexamined Patent Application No. 59-179816
discloses a titled graphite fiber having high electrical
conductivity comparable with metal, good wetting properties with
metal, and stability in air, wherein FeCl.sub.3 is penetrated into
the crystal face of graphite fiber having a concentric crystal
structure to form an interlaminar compound. Graphite fiber and
FeCl.sub.3 are placed in a glass tube, heated preferably at
250.degree.-400.degree. C. under reduced pressure wherein
FeCl.sub.3 is evaporated and the interior of the tube is kept in an
atmosphere of FeCl.sub.3 gas to give the desired graphite fiber
wherein FeCl.sub.3 is penetrated into the crystal face of the
graphite fiber having concentric crystal structure to form an
interlaminar compound.
The carbon fiber should be mixed in the precursor of the
polyurethane resin prior to curing so that the precursor can be
fluid enough to be easily treated. After curing, the polyurethane
resin should contain between 5% and 30% by weight of the carbon
fiber. The polyurethane resin mixed with 5% to 30% by weight of the
carbon fiber has wear resistance and breaking strength. When the
double-liquid type of the precursor is used, the carbon fiber can
be mixed into both or either of the first and second liquids.
Packings or sealants composed of the polyurethane resin in which
20% to 30% by weight of the carbon fiber is mixed can have high
conductivity and strength, and can provide
electromagnetic-shielding effect.
If required, a known filler, plasticizer, or
deterioration-preventive agent can be mixed in the sealant compound
with the carbon fiber mixed therein so as to modify the properties
of the compound.
An O ring, a packing, or other formed seal of the compound of this
invention can be applied to gaps in a housing. A single-liquid type
of the compound is discharged in a strand of beads using a known
delivering apparatus to form a seal onto an edge of a housing, or
other place. By closing the housing with a cover, the seal adhering
to the edge fills the gap between the housing and the cover. A
double-liquid type of the compound is discharged using a known
fixed-amount delivering apparatus provided with a mixer. By mixing
first liquid with second liquid by the fixed amount, the compound
is discharged onto the edge of the housing to form the seal onto
the edge of the housing.
The single-liquid type compound can be supplied using a pail or a
cartridge and discharged mechanically or by using a manual gun.
When the sealant requires more adhesion, known various resins for
providing adhesion can be added to the sealant compound. A surface
can be coated with primer before the sealant is applied to the
surface so as to provide or enhance adhering effect.
Since conductive carbon fiber is used in the compound of this
invention, by adjusting the amount of the carbon fiber mixed into
the polyurethane resin, the sealant compound can have variable
conductivity. When the seal of the compound is applied to the
housing of electronic equipment, it can protect the electronic
equipment from dust, particles, moisture and toxic gas, and also
function as an electrostatic discharge shielding material to
protect the electronic equipment from static electricity. It can
also be used as a shielding material to prevent electromagnetic
waves from entering or leaking from the electronic equipment in the
housing. In combination with a magnetic substance, the seal can be
used as an electromagnetic-interference shielding material to
protect the electronic equipment or a magnetic recording element
from electromagnetic waves.
* * * * *